The present invention relates to an image sensing apparatus and method and, more particularly, to an image sensing apparatus and method utilizing an image sensing device, such as a CCD (charge coupled device).
A configuration of a conventional image sensing apparatus is shown in FIG. 11. Color filters are independently provided for even-numbered field and for odd-numbered field of a solid-state image sensing device 101 using interlace scanning, as shown in FIG. 4. Referring to FIG. 4, signals of Ye (yellow) and Cy (cyan) components are alternatively read out as VOUT1, and signals of Mg (magenta) and G (green) components are alternatively read out as VOUT2.
These signals outputted as VOUT1 and VOUT2 are applied with sample and hold processing in the sample and hold (S/H) circuits 102 and 103 shown in FIG. 11. Thereafter, the signals enter an automatic gain controller (AGC) where the signals are amplified with automatically controlled gains, then analog-digital converted to digital signals by an analog/digital (A/D) converters 106 and 107. The digital signals outputted from the A/D converters 106 and 107 enter memories 109 and 110 having the capacity to store television signals of one horizontal period (abbreviated as xe2x80x9c1Hxe2x80x9d, hereinafter) and are delayed there, as well as inputted to an adder 108 where added together. The outputs from the memories 109 and 110 enter an adder 111 where they are added. As a result of the addition, luminance signals are generated.
The outputs from the adders 108 and 111 enter low-pass filters 112 and 113, respectively, where color carrier signals are removed. The output from the low-pass filter 113 is delayed by using a memory 114 having a capacity of storing signals of 1H. The outputs from the low-pass filters 112 and 113 and the outputs from the memory 114 are luminance signals in continuous 3H. The luminance signals in continuous 3H are inputted into an aperture correction circuit 100 where high-frequency components of the inputted signals are extracted by using a high-pass filter 115 provided within the aperture correction circuit 100. Thereafter, noises are removed from the extracted high-frequency components of the signals by a base-clipping circuit 117, thereby an aperture correction signal in the vertical direction is produced. Meanwhile, high-frequency component of the output from the low-pass filter 113 is extracted by a high-pass filter 116, then noises are removed from the extracted high-frequency component by a base-clipping circuit 118, thereby an aperture correction signal in the horizontal direction is produced. These aperture correction signals in the vertical and horizontal directions are added by an adder 119, then the signal level of the added signal is adjusted by a gain controller 120 so as to restrain the gain upon aperture correction on a low luminance signal, thus a detail (DTL) signal is generated.
Then, aperture correction is performed in such a manner that the phase of the output from the low-pass filter 113 and the phase of the DTL signal are synchronized by using a delay circuit (not-shown) and the signals are added by an adder 121.
The luminance signals which are processed with the aperture correction is then amplified by a gain which is set to restrain the high luminance component in a knee circuit 122. Thereafter, the luminance signal is applied with xcex3 correction by a xcex3 correction circuit 123, further, appended with a blanking signal by a blanking signal appending circuit 124. Furthermore, the signal is digital-analog converted to an analog signal by a digital/analog (D/A) converter 125, passes through a low-pass filter 126, then becomes a video luminance signal YOUT.
Meanwhile, the outputs from the memories 109 and 110 are inputted to a synchronization/interpolation circuit 127 where each of color components (here, yellow (Y), cyan (Cy), magenta (Mg) and green (G) components) of the signals are synchronized. From these respective components, returned components are removed by low-pass filters 128 to 131. Further, a matrix operation,                               (                                                    R                                                                    G                                                                    B                                              )                =                              (                                                                                A                    11                                                                                        A                    12                                                                                        A                    13                                                                                        A                    14                                                                                                                    A                    21                                                                                        A                    22                                                                                        A                    23                                                                                        A                    24                                                                                                                    A                    31                                                                                        A                    32                                                                                        A                    33                                                                                        A                    34                                                                        )                    ⁢                      xe2x80x83                    ⁢                      (                                                            Ye                                                                              Cy                                                                              Mg                                                                              G                                                      )                                              Equation        ⁢                  xe2x80x83                ⁢        1            
is performed in a matrix operation circuit 132 to obtain R, G and B components. These R, G and B components are applied with white balance correction controlling their gains with respect to the gain of the G component by a multipliers 133 and 134 in a white balance circuit. Each of the R, G and B components which are processed with the white balance correction is added to the DTL signal outputted from the gain controller 120 in a corresponding adder 135, 136 or 137. Thereby, high frequency components of the R, G and B components are enhanced.
The color signals are then amplified with gains which are set to restrain high luminance component in respective knee circuits 138 to 140, further applied with the xcex3 correction in xcex3 correction circuits 141 to 143. Thereafter, color difference signals R-Y and B-Y are generated by performing the following operation,                               (                                                                      R                  -                  G                                                                                                      B                  -                  Y                                                              )                =                              (                                                                                B                    11                                                                                        B                    12                                                                                        B                    13                                                                                                                    B                    21                                                                                        B                    22                                                                                        B                    23                                                                        )                    ⁢                      xe2x80x83                    ⁢                      (                                                            R                                                                              G                                                                              B                                                      )                                              Equation        ⁢                  xe2x80x83                ⁢        2            
in a matrix operation circuit 144. After hues of these color difference signals are corrected in a hue correction circuit 145, high-frequency components of the corrected color difference signals are removed by low-pass filters 146 and 147 so as to become suitable to subsequent modulation. Next, the signals are modulated and appended with a burst signal in a modulation circuit, then converted to an analog signal by a D/A converter 149. Thereafter, the signal pass through a low-pass filter 150 to be a video color signal COUT.
Further, the outputs from the respective knee circuits 138 to 140 and the respective outputs from the xcex3 correction circuits 141 to 143 are sent to respective selectors 151 to 153. The selected signals are added with blanking signals in blanking signal appending circuits 154 to 156, thus become red digital signals ROUT, green digital signals GOUT and blue digital signals BOUT. These digital signals are inputted to a multimedia device (not-shown), such as a computer and a printer. The selectors 151 to 153 select the signals depending upon whether the multimedia device requires the xcex3 correction or not.
However, according to the aforesaid conventional apparatus, interpolation is performed prior to the matrix operation for obtaining R, G and B components upon synchronizing respective color components of signals inputted from the CCD, frequency band of signals in the horizontal direction is narrow. This does not affect quality of an image when the signals are outputted on a television monitor. However, when the image is displayed based on the R, G and B digital signals on a display of a multimedia device, such as a computer and a printer, it causes a problem in which satisfactory resolution can not be achieved and reproduced colors are blur. The drop of the quality of resolution and blur in color are noticeable especially in a still image.
Further, an aperture correction component of luminance signal is added to R, G and B components to achieve a high quality image. However, by doing so, when a moving image is to be outputted by a printer as a still image, dark parts of the image have dazzling texture because the aperture correction signals in the low frequency component is not constrained enough and noise components are not removed satisfactorily.
The present invention has been made in consideration of the above situation, and has as its object to realize improvement in image quality, when image signals are to be outputted on a multimedia device, by switching contents of luminance signal processing and of color signal processing depending upon whether a moving image or a still image is inputted.
According to the present invention, the foregoing object is attained by providing an image sensing apparatus comprising: image sensing means for sensing an image of an object and generating first image signals and second image signals; delaying means for delaying the first image signals for a predetermined time period and outputting delayed image signals corresponding to each of the first image signals; detecting means for detecting movement of the image on the basis of comparing the second image signals against the delayed image signals; and first processing means for applying a predetermined image process to color components of the second and delayed image signals or of the first image signals in accordance with a detected result by the detecting means, wherein the first image signals are produced during first image scanning periods and the second image signals are produced during second image scanning periods, immediately following first image scanning periods.
In accordance with the present invention as described above, the image sensing apparatus further comprises matrix operation means for performing matrix operation on the image signals processed by the first processing means on the basis of the detected result by the detecting means.
Furthermore, in accordance with the present invention, the image sensing apparatus described further comprises second processing means for applying a predetermined image process on a luminance component of the first image signals in accordance with the detected result by the detecting means.
Further, the foregoing object is also attained by providing an image sensing method comprising: an image sensing step of sensing an image of an object and generating first image signals and second image signals; a delaying step of delaying the first image signals for a predetermined time period and outputting delayed image signals corresponding to each of the first image signals; a detecting step of detecting movement of the image on the basis of comparing the second image signals against a delayed image signals; and a first processing step of applying a predetermined image process to color components of the second and delayed image signals or of the first image signals in accordance with the detected result at the detecting step, wherein the first image signals are produced during first image scanning periods and the second image signals are produced during second image scanning periods, immediately following first image scanning periods.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.